- the "skill window" ui element is not that wide when u look at it in GUTS, but in-game it is wide! which property should i adjust so the GUTS view looks more like in-game?
- The "background" ui element is a child of the "skill window" ui element and they have the same width (narrow in GUTS). But because it "expands" in-game, i had to shrink the left-to-right dimension of the background image so it would also expand in-game
Very un-intuitive and a nightmare to adjust! What am i doing wrong here pls?
hm.. let me start this way: when you run TL2 in min resolution (800x600) and the UI-Scale set to 100% you still be able to have both menu sides open. This is why the menu buttons are on a different height (else they would overlap).
Any changes in menu size will result in overlapping BUT only in min resolution and 100% scale! I guess the majority will play in a higher resolution and prefer 90-80% UI scale so it should be fine.
The vanilla menu size is 715x510, I guess you would be fine with 715x765 or something like that.
I've seen your file is larger then the size you set in guts, so I decided to quickly adjust that... Its in the dropbox now (i've uploaded the photoshop file too so you might have a look how Ive done it)
To test it out I've cloned your skilltreeoverride and filled in my piece but I noticed wrong locations here and there so I copied the vanilla skilltree and pasted it right into my skilltree. they were ofcorse overlapping so I've set the visibility to false. from there I went through all the major elements and double-checked the size and offsets.
You still had a lot of elements with scaling properties so I fixed them and relocated the buttons aund windows with XnY offset. Mainly by copying the vanilla values and adjusting the width here and there.
now the background image fits perfectly - though it still appears too small in GUTS - this is where you might need photoshop creating a collage of your element like in GUTS and mesure their position, then head over to guts and place them there, even if they wont fit with the background (for the moment - in game they will!).
#EDIT will upload it too so you can have a look. though the imagesize is not optimal! the menu is called Skilltree_lolesch and you have to bind it to the unittype but you know that

- I notice when you move a "window" all items inside the window move together. So when setting offset, do i offset against the parent window or something else? does their alignment setting affect this?
- can different items have different alignment settings? like some are left, some are right / or do they all have to use the same alignment setting?
Yeah, "windows" are containers, moving to will move the inside too. You always offset to the parent and use the alignments so left, top with x=10 y=10 will move it right and down. right, center with x=-10 y=10 will move it right and down

The alignment is the corner you start from. positive numbers will move in the opposite direction, negatives in the same... I never made that clear to myself in that way but I guess you got it.
Different Items can have different alignments, yes! I recommend to use the same alignments for same elements, lets say all your skills, because if you adjust the parent window size elements using the top left will move in the opposite direction the elements using bottom right. Relatively tho their "corner" they do keep the offset.
sorry for not going into UI Logic so far... I will give some light there as soon as possible. As well as for the tooltip (wich is UI so you can mod it

the UI skill properties direct to it)
I'd do a multilevel skill - feels more comfortable to me but you are the skill master not me

About the Tooltip
Will the choice of separate skill/multi-level skill affect what we can do with the tooltip?
yes. and no. the tooltip reads through the skills actual level. so different level with different affixes will result in different tooltips - no need of different skills here.
I was thinking the standard skill tooltip doesnt look good for the training skills - each tooltip will always show "rank 1/1", or hovering over each mini-icon pops up the same looking tooltip every time and the tooltip is too big, etc, etc.
what do you think?
totally manageable. as said above you can mod the tooltip itself/create a now tooltip just for the training skill.
Or an alternative would be to just keep clicking the first skill icon/plus sign, and have a "progress bar" that keeps extending to the right. Is that possible/advisable?
I like it. but you can also remove the tooltips from the buttons and just ad a hover description so the tooltip only shows up on the "training skill icon" and the further buttons just say something like "increase trainingskill" or so.
this way you would need a multi-level-skill!
this is just written in a hurry, sorry. always happy to answer your questions (hope i did answer most of them) and keep me updated!
lolesch